This invention relates generally to surgical instruments and, more particularly, to a device for percutaneous incisional breast biopsy.
The early diagnosis of breast cancer through the use of mammography is very important for reducing the morbidity associated with breast cancer. Early diagnosis enables a physician to treat the breast cancer at a more manageable stage of development.
Mammography is capable of detecting very small abnormalities in breast tissue. However, mammography usually cannot differentiate between malignant and benign lesions in the breast. Definitive determination of the status of a lesion often requires a histological examination of the suspect tissue.
One method for obtaining a tissue sample for histological examination is through a biopsy of part or all of the suspect tissue. There are a number of devices and methods for performing a biopsy of the breast. Generally, the procedure requires first placing a localization needle within or near the lesion. A guide wire contained within the localization needle is then deployed. The guide wire usually includes hooks that anchor one end of the guide wire in breast tissue near the lesion. Then a biopsy device that includes a cannula and a stylet that is located within the cannula is inserted over the localization needle and guide wire. The device is inserted through a small incision in the breast tissue near the entry point of the localization needle. The stylet bluntly separates breast tissue as the device is inserted down the guide wire toward the lesion. Advancement of the device is stopped once the tip of the stylet is within or near the lesion. Then, the cannula, which has a cutting surface at its leading edge, is advanced over the stylet and into the tissue thereby cutting a core of tissue. The cutting surface is advanced to a point beyond the end of the guide wire. Then, a second cutting surface, typically a wire garrote, is activated to perform a cut transverse to the direction the cannula and beyond the end of the guide wire. This second cut releases a plug from the lesion. Then the needle, guide wire, and device are retracted from the breast with the plug. The plug is then histologically examined to determine whether the suspect tissue is malignant or benign.
The current devices have a number of disadvantages including: the device, localization needle, and guide wire are not manufactured as a single unit; and the devices generally do not have a means for insuring that the garrote wire is located past the end of the guide wire prior to deployment of the garrote. In order to determine whether the garrote is located past the end of the guidewire, a radiographic check is required. Further, the blunt stylet requires substantial force to insert and may cause trauma to the healthy tissue as it passes to the biopsy site.
Therefore, it is desirable to provide a biopsy device manufactured as a unit with a localization needle and a guide wire. Additionally, it is desirable to provide a biopsy device having features to insure that the garrote wire is not deployed until it is past the end of the guide wire. It is also desirable to provide a stylet with cutting members to transect and separate breast tissue and minimize the damage to healthy tissue.